The invention relates to heater assemblies, such as gas fired water heaters, and more particularly to a flame powered logic supply circuit supplying electrical energy to power electronic logic circuitry for the heater and/or for indicia purposes.
A gas fired water heater has an inner storage tank for storing water to be heated, a main burner below the tank for heating the water in the tank, and a pilot for igniting the burner. The present invention provides particularly simple and effective circuitry responsive to the pilot flame and supplying electrical energy to power electronic logic circuitry for the water heater. The circuit enables the pilot flame to generate sufficient energy to drive electronic logic circuitry such as monitoring circuitry including LCDs (liquid crystal displays) for water temperature, time of day, set back time, flue gas temperature, etc. The supply circuit enables the pilot flame to be a stand alone power source, with or without a backup battery The invention has application to various other types of heater assemblies, such as furnaces, hydronic heaters, and so on.
In further embodiments, a second flame powered supply circuit is provided for the main burner, in addition to the flame powered supply circuit for the pilot. The supply circuits include indicia, such as LEDs (light emitting diodes) providing an indication that current is flowing therethrough and hence that the respective flame is lit.
In another implementation, a flame powered supply circuit is provided for the main burner and provides charging current for a battery which powers electronic logic circuitry for the heater. This implementation is particularly desirable in pilotless ignition systems where there may be long gaps of time between usage of the main burner.